| 摘要 |
A compressed gas cartridge to be fired in an air gun has an outer casing 100 and a valve member 102 extending therein to seal apertures at both ends of the casing (but axially displaceable at the discharge end to propel a missile 118 by means of a firing lever 116). The apertures sealed are of unequal area so that a resultant force on the valve member due to gas pressure within the cartridge seals the valve head 102A against the valve seat 105 to. The cartridge may be charged through the discharge end by means of a union (120) coupled to the source of compressed gas which retains the valve member 102 at the discharge end against movement whilst allowing the casing to slide relatively to the union. By appropriately biasing the casing, the movement thereof is effective to impart a non-return action to the discharge valve of the cartridge. In a gun for firing the cartridge the lever 116 is coupled to a toggle linkage formed by trigger 141 and links 143 which in an overcentre position transmits force with substantial mechanical advantage. The lever 116 and toggle form a trapezium linkage which allows rearward pivoting of the lever to free the cartridge chamber. <IMAGE> |
